Systems and methods for controlling super capacitor charge voltage to extend super capacitor life

ABSTRACT

A method of determining a lifetime parameter of a capacitor in a failsafe device includes measuring an amount of energy required to return the failsafe device to a failsafe position, measuring an effective capacitance of the capacitor, and comparing the amount of energy to the effective capacitance to determine the lifetime parameter of the capacitor.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

The present application claims the benefit of and priority to U.S.Provisional Application No. 63/144,446, filed on Feb. 1, 2021. Thisapplication is also a continuation-in-part of U.S. patent applicationSer. No. 16/574,806, filed on Sep. 18, 2019, which claims the benefit ofand priority to U.S. Provisional Application No. 62/733,584, filed onSep. 19, 2018. The above-referenced applications are incorporated byreference herein in their entireties.

BACKGROUND

The present disclosure relates generally to the field of supercapacitors, and more particularly to systems and methods for extendingthe life of super capacitors.

Unlike ordinary capacitors, super capacitors do not use the conventionalsolid dielectric, but rather, they use electrostatic double-layercapacitance and electrochemical pseudocapacitance, both of whichcontribute to the total capacitance of the capacitor. Specifically,electrostatic double-layer capacitors (“EDLC”) use carbon electrodes orderivatives with much higher electrostatic double-layer capacitance thanelectrochemical pseudocapacitance. Separation of charge is achieved inEDLCs by using a Helmholtz double layer. The separation of charge is ofthe order of a few angstroms (0.3-0.8 nm), much smaller than in aconventional capacitor. By having a much smaller separation of charge,super capacitors are able to have a much greater capacitance than inconventional capacitors.

Super capacitors may be used throughout a building management system(“BMS”). A BMS is, in general, a system of devices configured tocontrol, monitor, and manage equipment in or around a building orbuilding area. A BMS may include a heating, ventilation, and airconditioning (“HVAC”) system, a security system, a lighting system, afire alerting system, another system that is capable of managingbuilding functions or devices, or any combination thereof. BMS devicesmay be installed in any environment (e.g., an indoor area or an outdoorarea) and the environment may include any number of buildings, spaces,zones, rooms, or areas. A BMS may include a variety of devices (e.g.,HVAC devices, controllers, chillers, fans, sensors, etc.) configured tofacilitate monitoring and controlling the building space. Supercapacitors may be included in BMS devices.

Currently, many building management systems provide control of an entirefacility, building, or other environment. For example, a buildingmanagement system may be configured to monitor multiple buildings, eachhaving HVAC systems, water system, lights, air quality, security, and/orany other aspect of the facility within the purview of the buildingmanagement system.

Super capacitors may experience aging during use. Aging may result indecreased capacitance and increased internal resistance. Aging may beaccelerated with exposure to high temperatures and high operatingvoltages. As a result, the super capacitor may still be operable, butthe capabilities may be significantly reduced (e.g., as a supercapacitor ages, the amount of energy it may store will decrease). Somesystems operate super capacitors at their rated voltage, which increasesthe energy stored, but may shorten the operating life of the supercapacitor. Other systems operate super capacitors at a voltage lowerthan the rated voltage, which may prolong the life of the supercapacitor, but results in decreased energy storage. Accordingly, thereexists a tradeoff between energy storage and super capacitor life.

SUMMARY

One implementation of the present disclosure is a method of determininga lifetime for a capacitor in a failsafe device. The method includesmeasuring an amount of energy required to return the failsafe device toa failsafe position, measuring an effective capacitance of thecapacitor, comparing the amount of energy to the effective capacitanceto determine the lifetime parameter of the capacitor.

In some embodiments, the method further includes determining, based onthe effective capacitance, a charge voltage for the capacitor, andcharging the capacitor using the charge voltage. In some embodiments,the lifetime parameter is a length of time associated with a remainingoperational period of the capacitor. In some embodiments, the failsafedevice is an actuator. In some embodiments, the lifetime parameter is anamount of time required to charge the capacitor to a level associatedwith the amount of energy required to return the failsafe device to thefailsafe position. In some embodiments, the lifetime parameter isdiagnostic information associated with physically testing an ability ofthe capacitor to return the failsafe device to the failsafe position. Insome embodiments, the method further includes sending the lifetimeparameter to a building management system (BMS), and the lifetimeparameter indicates that the capacitor should be replaced.

Another implementation of the present disclosure is a method of charginga capacitor in a failsafe device. The method includes measuring anamount of energy required to return the failsafe device to a failsafeposition, measuring an effective capacitance of the capacitor,determining, based on the effective capacitance and the amount ofenergy, a charge voltage for the capacitor, and charging the capacitorusing the charge voltage.

In some embodiments, the failsafe device is an actuator. In someembodiments, the method further includes comparing the amount of energyto the effective capacitance to determine a lifetime parameter of thecapacitor, and sending the lifetime parameter. In some embodiments, thelifetime parameter indicates that the capacitor should be replaced. Insome embodiments, the lifetime parameter is a length of time associatedwith a remaining operational period of the capacitor. In someembodiments, the lifetime parameter is an amount of time required tocharge the capacitor to a level associated with the amount of energyrequired to return the failsafe device to the failsafe position. In someembodiments, the lifetime parameter is diagnostic information associatedwith physically testing an ability of the capacitor to return thefailsafe device to the failsafe position.

Another implementation of the present disclosure is a failsafe deviceassembly including an actuator, a capacitor, and a processing circuitincluding a processor and memory. The memory includes instructionsstored thereon that, when executed by the processor, cause theprocessing circuit to measure an amount of energy required to return theactuator to a failsafe position, measure an effective capacitance of thecapacitor, compare the amount of energy to the effective capacitance todetermine an operational parameter of the actuator, and operate theactuator according to the operational parameter.

In some embodiments, the memory has further instructions stored thereonthat, when executed by the processor, cause the processing circuit todetermine, based on the effective capacitance, a charge voltage for thecapacitor, and charge the capacitor using the charge voltage.

In some embodiments, measuring the effective capacitance includescharging the capacitor to full charge, measuring a first voltage of thecapacitor, discharging the capacitor through a known load, measuring thecurrent associated with the discharging, and measuring a second voltageof the capacitor. In some embodiments, measuring the amount of energyrequired to return the actuator to the failsafe position includesdriving the actuator from a first position to a second position, andmeasuring an amount of energy associated with driving the actuator fromthe first position to the second position. In some embodiments, a rangeof movement of the actuator is greater than a range of movement betweenthe first position and the second position. In some embodiments, theindication signals that the capacitor should be replaced.

Another implementation of the present disclosure is a method ofdetermining a lifetime parameter of a capacitor in a failsafe deviceincluding measuring an amount of energy required to return the failsafedevice to a failsafe position, measuring an effective capacitance of thecapacitor, comparing the amount of energy to the effective capacitanceto determine the lifetime parameter of the capacitor, and sending thelifetime parameter of the capacitor.

In some embodiments, the method further includes determining, based onthe effective capacitance, a charge voltage for the capacitor, andcharging the capacitor using the charge voltage. In some embodiments,the lifetime parameter is a length of time associated with a remainingoperational period of the capacitor. In some embodiments, the failsafedevice is an actuator. In some embodiments, the lifetime parameter is anamount of time required to charge the capacitor to a level associatedwith the amount of energy required to return the failsafe device to thefailsafe position. In some embodiments, the lifetime parameter isdiagnostic information associated with physically testing an ability ofthe capacitor to return the failsafe device to the failsafe position. Insome embodiments, the indication signals that the capacitor should bereplaced.

Another implementation of the present disclosure is a method of charginga capacitor in a failsafe device including measuring an amount of energyrequired to return the failsafe device to a failsafe position, measuringan effective capacitance of the capacitor, determining, based on theeffective capacitance and the amount of energy, a charge voltage for thecapacitor, and charging the capacitor using the charge voltage.

In some embodiments, the failsafe device is an actuator. In someembodiments, the method further includes comparing the amount of energyto the effective capacitance to determine a lifetime parameter of thecapacitor, and sending an indication of the lifetime parameter. In someembodiments, the indication signals that the capacitor should bereplaced. In some embodiments, the indication is a length of timeassociated with a remaining operational period of the capacitor. In someembodiments, the indication is an amount of time required to charge thecapacitor to a level associated with the amount of energy required toreturn the failsafe device to the failsafe position. In someembodiments, the indication is diagnostic information associated withphysically testing an ability of the capacitor to return the failsafedevice to the failsafe position.

Another implementation of the present disclosure is a failsafe deviceassembly including an actuator, a capacitor, and a processing circuitincluding a processor and memory, the memory having instructions storedthereon that, when executed by the processor, cause the processingcircuit to measure an amount of energy required to return the actuatorto a failsafe position, measure an effective capacitance of thecapacitor, compare the amount of energy to the effective capacitance todetermine an operational parameter of the actuator, and operate theactuator according to the operational parameter.

In some embodiments, the memory has further instructions stored thereonthat, when executed by the processor, cause the processing circuit todetermine, based on the effective capacitance, a charge voltage for thecapacitor, and charge the capacitor using the charge voltage. In someembodiments, the operational parameter describes a speed with which theactuator returns to the failsafe position. In some embodiments,determining the operational parameter of the actuator further includesreceiving a selection of the speed from a user. In some embodiments, thememory further includes instructions stored thereon that, when executedby the processor, cause the processing circuit to compare the amount ofenergy to the effective capacitance to determine a lifetime parameter ofthe actuator and send the lifetime parameter. In some embodiments, thelifetime parameter indicates that the capacitor should be replaced. Insome embodiments, the failsafe device assembly further includes anartificial intelligence module.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a drawing of a building equipped with a HVAC system, accordingto some embodiments.

FIG. 2 is a block diagram of a waterside system which may be used toserve the building of FIG. 1, according to some embodiments.

FIG. 3 is a block diagram of an airside system which may be used toserve the building of FIG. 1, according to some embodiments.

FIG. 4 is a block diagram of a building management system (BMS) whichmay be used to monitor and control the building of FIG. 1, according tosome embodiments.

FIG. 5 is a block diagram of an actuator that includes a super capacitorwith adjustable charge voltage, according to some embodiments.

FIG. 6 is a flowchart of a process for controlling charge voltage of asuper capacitor, according to some embodiments.

FIG. 7 is a flowchart of a process for determining an energy valuecorresponding to an actuator operation, according to some embodiments.

FIG. 8 is a flowchart of a process for determining parameters associatedwith a failsafe device, according to some embodiments.

FIG. 9A is a flowchart of a process for determining a lifetime of acapacitor, according to some embodiments.

FIG. 9B is a flowchart of a process for determining a speed with whichto drive a failsafe device, according to some embodiments.

FIG. 10 is a flowchart of a process for determining a time required tocharge a capacitor, according to some embodiments.

FIG. 11 is a diagram of a boost-buck converter for charging the supercapacitor, according to some embodiments.

DETAILED DESCRIPTION Overview

Super capacitors are generally used in applications requiring many rapidcharge/discharge cycles rather than long term compact energy storage.For example, super capacitors may be used within cars, buses, trains,cranes and elevators, where they are used for regenerative braking,short-term energy storage, or burst-mode power delivery.

As indicated above, super capacitors generally have a “rated voltage.”The rated voltage corresponds to a maximum voltage level that should beused to charge the super capacitor. Typically, the rated voltage mayinclude a safety margin to prevent accidental decomposition of theelectrolyte.

As described above, some systems operate super capacitors at their ratedvoltage, which increases the energy stored, but may shorten theoperating life of the super capacitor. Other systems operate supercapacitors at a voltage lower than the rated voltage, which may prolongthe life of the super capacitor, but results in decreased energystorage. Accordingly, there exists a tradeoff between energy storage andthe life of the super capacitor.

The present disclosure is directed towards measuring and extending thelife of a capacitor and controlling operation of a failsafe device basedon the measured lifetime of the capacitor. In some embodiments, thepresent disclosure includes systems and methods for determining andimplementing a minimum required operating voltage (e.g., the voltageneeded to produce a predetermined output in a device).

As one example, a minimum required operating voltage that corresponds toproper operating of a failsafe return (i.e., an actuator returns to adefault position when power is removed) may be determined andimplemented. In some embodiments, the capacitance of the super capacitormay be measured by a controller at an initial charging state, after thedevice (e.g., actuator) is powered. Based on the capacitancemeasurement, the appropriate operating voltage (i.e., charge voltage)may be configured by the controller. Accordingly, the super capacitormay be configured to be charged to lower voltages at the start of itslife cycle (which may reduce aging), and charged to higher voltageslater in the life cycle (which may offset capacitance reduction).

In some embodiments, the present disclosure includes systems and methodsfor controlling operation of a failsafe device based on measuredcharacteristics of the capacitor. As one example, a controller maydetermine the energy required to operate a failsafe device (e.g., returnthe failsafe device to a failsafe position). Based on the energydetermination, a lifetime of an associated capacitor (e.g., a failsafecapacitor) may be determined by the controller. Accordingly, thefailsafe device (e.g., an actuator, etc.) may be configured to operateat slower speeds (which may offset capacitance reduction). Additionallyor alternatively, the controller may collect diagnostics associated withthe failsafe device to determine when the device (or components thereof)need to be replaced and/or to send an indication of the lifetime of thedevice.

Building HVAC Systems and Building Management Systems

Referring now to FIGS. 1-4, several building management systems (BMS)and HVAC systems in which the systems and methods of the presentdisclosure may be implemented are shown, according to some embodiments.In brief overview, FIG. 1 shows a building 10 equipped with a HVACsystem 100. FIG. 2 is a block diagram of a waterside system 200 whichmay be used to serve building 10. FIG. 3 is a block diagram of anairside system 300 which may be used to serve building 10. FIG. 4 is ablock diagram of a BMS which may be used to monitor and control building10.

Building and HVAC System

Referring particularly to FIG. 1, a perspective view of a building 10 isshown. Building 10 is served by a BMS. A BMS is, in general, a system ofdevices configured to control, monitor, and manage equipment in oraround a building or building area. A BMS may include, for example, aHVAC system, a security system, a lighting system, a fire alertingsystem, any other system that is capable of managing building functionsor devices, or any combination thereof.

The BMS that serves building 10 includes a HVAC system 100. HVAC system100 may include a plurality of HVAC devices (e.g., heaters, chillers,air handling units, pumps, fans, thermal energy storage, etc.)configured to provide heating, cooling, ventilation, or other servicesfor building 10. For example, HVAC system 100 is shown to include awaterside system 120 and an airside system 130. Waterside system 120 mayprovide a heated or chilled fluid to an air handling unit of airsidesystem 130. Airside system 130 may use the heated or chilled fluid toheat or cool an airflow provided to building 10. An exemplary watersidesystem and airside system which may be used in HVAC system 100 aredescribed in greater detail with reference to FIGS. 2-3.

HVAC system 100 is shown to include a chiller 102, a boiler 104, and arooftop air handling unit (AHU) 106. Waterside system 120 may use boiler104 and chiller 102 to heat or cool a working fluid (e.g., water,glycol, etc.) and may circulate the working fluid to AHU 106. In variousembodiments, the HVAC devices of waterside system 120 may be located inor around building 10 (as shown in FIG. 1) or at an offsite locationsuch as a central plant (e.g., a chiller plant, a steam plant, a heatplant, etc.). The working fluid may be heated in boiler 104 or cooled inchiller 102, depending on whether heating or cooling is required inbuilding 10. Boiler 104 may add heat to the circulated fluid, forexample, by burning a combustible material (e.g., natural gas) or usingan electric heating element. Chiller 102 may place the circulated fluidin a heat exchange relationship with another fluid (e.g., a refrigerant)in a heat exchanger (e.g., an evaporator) to absorb heat from thecirculated fluid. The working fluid from chiller 102 and/or boiler 104may be transported to AHU 106 via piping 108.

AHU 106 may place the working fluid in a heat exchange relationship withan airflow passing through AHU 106 (e.g., via one or more stages ofcooling coils and/or heating coils). The airflow may be, for example,outside air, return air from within building 10, or a combination ofboth. AHU 106 may transfer heat between the airflow and the workingfluid to provide heating or cooling for the airflow. For example, AHU106 may include one or more fans or blowers configured to pass theairflow over or through a heat exchanger including the working fluid.The working fluid may then return to chiller 102 or boiler 104 viapiping 110.

Airside system 130 may deliver the airflow supplied by AHU 106 (i.e.,the supply airflow) to building 10 via air supply ducts 112 and mayprovide return air from building 10 to AHU 106 via air return ducts 114.In some embodiments, airside system 130 includes multiple variable airvolume (VAV) units 116. For example, airside system 130 is shown toinclude a separate VAV unit 116 on each floor or zone of building 10.VAV units 116 may include dampers or other flow control elements thatmay be operated to control an amount of the supply airflow provided toindividual zones of building 10. In other embodiments, airside system130 delivers the supply airflow into one or more zones of building 10(e.g., via supply ducts 112) without using intermediate VAV units 116 orother flow control elements. AHU 106 may include various sensors (e.g.,temperature sensors, pressure sensors, etc.) configured to measureattributes of the supply airflow. AHU 106 may receive input from sensorslocated within AHU 106 and/or within the building zone and may adjustthe flow rate, temperature, or other attributes of the supply airflowthrough AHU 106 to achieve set point conditions for the building zone.

Waterside System

Referring now to FIG. 2, a block diagram of a waterside system 200 isshown, according to some embodiments. In various embodiments, watersidesystem 200 may supplement or replace waterside system 120 in HVAC system100 or may be implemented separate from HVAC system 100. Whenimplemented in HVAC system 100, waterside system 200 may include asubset of the HVAC devices in HVAC system 100 (e.g., boiler 104, chiller102, pumps, valves, etc.) and may operate to supply a heated or chilledfluid to AHU 106. The HVAC devices of waterside system 200 may belocated within building 10 (e.g., as components of waterside system 120)or at an offsite location such as a central plant.

In FIG. 2, waterside system 200 is shown as a central plant having aplurality of subplants 202-212. Subplants 202-212 are shown to include aheater subplant 202, a heat recovery chiller subplant 204, a chillersubplant 206, a cooling tower subplant 208, a hot thermal energy storage(TES) subplant 210, and a cold thermal energy storage (TES) subplant212. Subplants 202-212 consume resources (e.g., water, natural gas,electricity, etc.) from utilities to serve thermal energy loads (e.g.,hot water, cold water, heating, cooling, etc.) of a building or campus.For example, heater subplant 202 may be configured to heat water in ahot water loop 214 that circulates the hot water between heater subplant202 and building 10. Chiller subplant 206 may be configured to chillwater in a cold water loop 216 that circulates the cold water betweenchiller subplant 206 building 10. Heat recovery chiller subplant 204 maybe configured to transfer heat from cold water loop 216 to hot waterloop 214 to provide additional heating for the hot water and additionalcooling for the cold water. Condenser water loop 218 may absorb heatfrom the cold water in chiller subplant 206 and reject the absorbed heatin cooling tower subplant 208 or transfer the absorbed heat to hot waterloop 214. Hot TES subplant 210 and cold TES subplant 212 may store hotand cold thermal energy, respectively, for subsequent use.

Hot water loop 214 and cold water loop 216 may deliver the heated and/orchilled water to air handlers located on the rooftop of building 10(e.g., AHU 106) or to individual floors or zones of building 10 (e.g.,VAV units 116). The air handlers push air past heat exchangers (e.g.,heating coils or cooling coils) through which the water flows to provideheating or cooling for the air. The heated or cooled air may bedelivered to individual zones of building 10 to serve thermal energyloads of building 10. The water then returns to subplants 202-212 toreceive further heating or cooling.

Although subplants 202-212 are shown and described as heating andcooling water for circulation to a building, it is understood that anyother type of working fluid (e.g., glycol, CO2, etc.) may be used inplace of or in addition to water to serve thermal energy loads. In otherembodiments, subplants 202-212 may provide heating and/or coolingdirectly to the building or campus without requiring an intermediateheat transfer fluid. These and other variations to waterside system 200are within the teachings of the present disclosure.

Each of subplants 202-212 may include a variety of equipment configuredto facilitate the functions of the subplant. For example, heatersubplant 202 is shown to include a plurality of heating elements 220(e.g., boilers, electric heaters, etc.) configured to add heat to thehot water in hot water loop 214. Heater subplant 202 is also shown toinclude several pumps 222 and 224 configured to circulate the hot waterin hot water loop 214 and to control the flow rate of the hot waterthrough individual heating elements 220. Chiller subplant 206 is shownto include a plurality of chillers 232 configured to remove heat fromthe cold water in cold water loop 216. Chiller subplant 206 is alsoshown to include several pumps 234 and 236 configured to circulate thecold water in cold water loop 216 and to control the flow rate of thecold water through individual chillers 232.

Heat recovery chiller subplant 204 is shown to include a plurality ofheat recovery heat exchangers 226 (e.g., refrigeration circuits)configured to transfer heat from cold water loop 216 to hot water loop214. Heat recovery chiller subplant 204 is also shown to include severalpumps 228 and 230 configured to circulate the hot water and/or coldwater through heat recovery heat exchangers 226 and to control the flowrate of the water through individual heat recovery heat exchangers 226.Cooling tower subplant 208 is shown to include a plurality of coolingtowers 238 configured to remove heat from the condenser water incondenser water loop 218. Cooling tower subplant 208 is also shown toinclude several pumps 240 configured to circulate the condenser water incondenser water loop 218 and to control the flow rate of the condenserwater through individual cooling towers 238.

Hot TES subplant 210 is shown to include a hot TES tank 242 configuredto store the hot water for later use. Hot TES subplant 210 may alsoinclude one or more pumps or valves configured to control the flow rateof the hot water into or out of hot TES tank 242. Cold TES subplant 212is shown to include cold TES tanks 244 configured to store the coldwater for later use. Cold TES subplant 212 may also include one or morepumps or valves configured to control the flow rate of the cold waterinto or out of cold TES tanks 244.

In some embodiments, one or more of the pumps in waterside system 200(e.g., pumps 222, 224, 228, 230, 234, 236, and/or 240) or pipelines inwaterside system 200 include an isolation valve associated therewith.Isolation valves may be integrated with the pumps or positioned upstreamor downstream of the pumps to control the fluid flows in watersidesystem 200. In various embodiments, waterside system 200 may includemore, fewer, or different types of devices and/or subplants based on theparticular configuration of waterside system 200 and the types of loadsserved by waterside system 200.

Airside System

Referring now to FIG. 3, a block diagram of an airside system 300 isshown, according to some embodiments. In various embodiments, airsidesystem 300 may supplement or replace airside system 130 in HVAC system100 or may be implemented separate from HVAC system 100. Whenimplemented in HVAC system 100, airside system 300 may include a subsetof the HVAC devices in HVAC system 100 (e.g., AHU 106, VAV units 116,ducts 112-114, fans, dampers, etc.) and may be located in or aroundbuilding 10. Airside system 300 may operate to heat or cool an airflowprovided to building 10 using a heated or chilled fluid provided bywaterside system 200.

In FIG. 3, airside system 300 is shown to include an economizer-type airhandling unit (AHU) 302. Economizer-type AHUs vary the amount of outsideair and return air used by the air handling unit for heating or cooling.For example, AHU 302 may receive return air 304 from building zone 306via return air duct 308 and may deliver supply air 310 to building zone306 via supply air duct 312. In some embodiments, AHU 302 is a rooftopunit located on the roof of building 10 (e.g., AHU 106 as shown inFIG. 1) or otherwise positioned to receive both return air 304 andoutside air 314. AHU 302 may be configured to operate exhaust air damper316, mixing damper 318, and outside air damper 320 to control an amountof outside air 314 and return air 304 that combine to form supply air310. Any return air 304 that does not pass through mixing damper 318 maybe exhausted from AHU 302 through exhaust damper 316 as exhaust air 322.

Each of dampers 316-320 may be operated by an actuator. For example,exhaust air damper 316 may be operated by actuator 324, mixing damper318 may be operated by actuator 326, and outside air damper 320 may beoperated by actuator 328. Actuators 324-328 may communicate with an AHUcontroller 330 via a communications link 332. Actuators 324-328 mayreceive control signals from AHU controller 330 and may provide feedbacksignals to AHU controller 330. Feedback signals may include, forexample, an indication of a current actuator or damper position, anamount of torque or force exerted by the actuator, diagnosticinformation (e.g., results of diagnostic tests performed by actuators324-328), status information, commissioning information, configurationsettings, calibration data, and/or other types of information or datathat may be collected, stored, or used by actuators 324-328. AHUcontroller 330 may be an economizer controller configured to use one ormore control algorithms (e.g., state-based algorithms, extremum seekingcontrol (ESC) algorithms, proportional-integral (PI) control algorithms,proportional-integral-derivative (PID) control algorithms, modelpredictive control (MPC) algorithms, feedback control algorithms, etc.)to control actuators 324-328.

Still referring to FIG. 3, AHU 302 is shown to include a cooling coil334, a heating coil 336, and a fan 338 positioned within supply air duct312. Fan 338 may be configured to force supply air 310 through coolingcoil 334 and/or heating coil 336 and provide supply air 310 to buildingzone 306. AHU controller 330 may communicate with fan 338 viacommunications link 340 to control a flow rate of supply air 310. Insome embodiments, AHU controller 330 controls an amount of heating orcooling applied to supply air 310 by modulating a speed of fan 338.

Cooling coil 334 may receive a chilled fluid from waterside system 200(e.g., from cold water loop 216) via piping 342 and may return thechilled fluid to waterside system 200 via piping 344. Valve 346 may bepositioned along piping 342 or piping 344 to control a flow rate of thechilled fluid through cooling coil 334. In some embodiments, coolingcoil 334 includes multiple stages of cooling coils that may beindependently activated and deactivated (e.g., by AHU controller 330, byBMS controller 366, etc.) to modulate an amount of cooling applied tosupply air 310.

Heating coil 336 may receive a heated fluid from waterside system 200(e.g., from hot water loop 214) via piping 348 and may return the heatedfluid to waterside system 200 via piping 350. Valve 352 may bepositioned along piping 348 or piping 350 to control a flow rate of theheated fluid through heating coil 336. In some embodiments, heating coil336 includes multiple stages of heating coils that may be independentlyactivated and deactivated (e.g., by AHU controller 330, by BMScontroller 366, etc.) to modulate an amount of heating applied to supplyair 310.

Each of valves 346 and 352 may be controlled by an actuator. Forexample, valve 346 may be controlled by actuator 354 and valve 352 maybe controlled by actuator 356. Actuators 354-356 may communicate withAHU controller 330 via communications links 358-360. Actuators 354-356may receive control signals from AHU controller 330 and may providefeedback signals to controller 330. In some embodiments, AHU controller330 receives a measurement of the supply air temperature from atemperature sensor 362 positioned in supply air duct 312 (e.g.,downstream of cooling coil 334 and/or heating coil 336). AHU controller330 may also receive a measurement of the temperature of building zone306 from a temperature sensor 364 located in building zone 306.

In some embodiments, AHU controller 330 operates valves 346 and 352 viaactuators 354-356 to modulate an amount of heating or cooling providedto supply air 310 (e.g., to achieve a setpoint temperature for supplyair 310 or to maintain the temperature of supply air 310 within asetpoint temperature range). The positions of valves 346 and 352 affectthe amount of heating or cooling provided to supply air 310 by coolingcoil 334 or heating coil 336 and may correlate with the amount of energyconsumed to achieve a desired supply air temperature. AHU 330 maycontrol the temperature of supply air 310 and/or building zone 306 byactivating or deactivating coils 334-336, adjusting a speed of fan 338,or a combination of both.

Still referring to FIG. 3, airside system 300 is shown to include abuilding management system (BMS) controller 366 and a client device 368.BMS controller 366 may include one or more computer systems (e.g.,servers, supervisory controllers, subsystem controllers, etc.) thatserve as system level controllers, application or data servers, headnodes, or master controllers for airside system 300, waterside system200, HVAC system 100, and/or other controllable systems that servebuilding 10. BMS controller 366 may communicate with multiple downstreambuilding systems or subsystems (e.g., HVAC system 100, a securitysystem, a lighting system, waterside system 200, etc.) via acommunications link 370 according to like or disparate protocols (e.g.,LON, BACnet, etc.). In various embodiments, AHU controller 330 and BMScontroller 366 may be separate (as shown in FIG. 3) or integrated. In anintegrated implementation, AHU controller 330 may be a software moduleconfigured for execution by a processor of BMS controller 366.

In some embodiments, AHU controller 330 receives information from BMScontroller 366 (e.g., commands, setpoints, operating boundaries, etc.)and provides information to BMS controller 366 (e.g., temperaturemeasurements, valve or actuator positions, operating statuses,diagnostics, etc.). For example, AHU controller 330 may provide BMScontroller 366 with temperature measurements from temperature sensors362-364, equipment on/off states, equipment operating capacities, and/orany other information that may be used by BMS controller 366 to monitoror control a variable state or condition within building zone 306.

Client device 368 may include one or more human-machine interfaces orclient interfaces (e.g., graphical user interfaces, reportinginterfaces, text-based computer interfaces, client-facing web services,web servers that provide pages to web clients, etc.) for controlling,viewing, or otherwise interacting with HVAC system 100, its subsystems,and/or devices. Client device 368 may be a computer workstation, aclient terminal, a remote or local interface, or any other type of userinterface device. Client device 368 may be a stationary terminal or amobile device. For example, client device 368 may be a desktop computer,a computer server with a user interface, a laptop computer, a tablet, asmartphone, a PDA, or any other type of mobile or non-mobile device.Client device 368 may communicate with BMS controller 366 and/or AHUcontroller 330 via communications link 372.

Building Management Systems

Referring now to FIG. 4, a block diagram of a building management system(BMS) 400 is shown, according to some embodiments. BMS 400 may beimplemented in building 10 to automatically monitor and control variousbuilding functions. BMS 400 is shown to include BMS controller 366 and aplurality of building subsystems 428. Building subsystems 428 are shownto include a building electrical subsystem 434, an informationcommunication technology (ICT) subsystem 436, a security subsystem 438,a HVAC subsystem 440, a lighting subsystem 442, a lift/escalatorssubsystem 432, and a fire safety subsystem 430. In various embodiments,building subsystems 428 may include fewer, additional, or alternativesubsystems. For example, building subsystems 428 may also oralternatively include a refrigeration subsystem, an advertising orsignage subsystem, a cooking subsystem, a vending subsystem, a printeror copy service subsystem, or any other type of building subsystem thatuses controllable equipment and/or sensors to monitor or controlbuilding 10. In some embodiments, building subsystems 428 includewaterside system 200 and/or airside system 300, as described withreference to FIGS. 2-3.

Each of building subsystems 428 may include any number of devices,controllers, and connections for completing its individual functions andcontrol activities. HVAC subsystem 440 may include many of the samecomponents as HVAC system 100, as described with reference to FIGS. 1-3.For example, HVAC subsystem 440 may include a chiller, a boiler, anynumber of air handling units, economizers, field controllers,supervisory controllers, actuators, temperature sensors, and otherdevices for controlling the temperature, humidity, airflow, or othervariable conditions within building 10. Lighting subsystem 442 mayinclude any number of light fixtures, ballasts, lighting sensors,dimmers, or other devices configured to controllably adjust the amountof light provided to a building space. Security subsystem 438 mayinclude occupancy sensors, video surveillance cameras, digital videorecorders, video processing servers, intrusion detection devices, accesscontrol devices and servers, or other security-related devices.

Still referring to FIG. 4, BMS controller 366 is shown to include acommunications interface 407 and a BMS interface 409. Interface 407 mayfacilitate communications between BMS controller 366 and externalapplications (e.g., monitoring and reporting applications 422,enterprise control applications 426, remote systems and applications444, applications residing on client devices 448, etc.) for allowinguser control, monitoring, and adjustment to BMS controller 366 and/orsubsystems 428. Interface 407 may also facilitate communications betweenBMS controller 366 and client devices 448. BMS interface 409 mayfacilitate communications between BMS controller 366 and buildingsubsystems 428 (e.g., HVAC, lighting security, lifts, powerdistribution, business, etc.).

Interfaces 407, 409 may be or include wired or wireless communicationsinterfaces (e.g., jacks, antennas, transmitters, receivers,transceivers, wire terminals, etc.) for conducting data communicationswith building subsystems 428 or other external systems or devices. Invarious embodiments, communications via interfaces 407, 409 may bedirect (e.g., local wired or wireless communications) or via acommunications network 446 (e.g., a WAN, the Internet, a cellularnetwork, etc.). For example, interfaces 407, 409 may include an Ethernetcard and port for sending and receiving data via an Ethernet-basedcommunications link or network. In another example, interfaces 407, 409may include a Wi-Fi transceiver for communicating via a wirelesscommunications network. In another example, one or both of interfaces407, 409 may include cellular or mobile phone communicationstransceivers. In one embodiment, communications interface 407 is a powerline communications interface and BMS interface 409 is an Ethernetinterface. In other embodiments, both communications interface 407 andBMS interface 409 are Ethernet interfaces or are the same Ethernetinterface.

Still referring to FIG. 4, BMS controller 366 is shown to include aprocessing circuit 404 including a processor 406 and memory 408.Processing circuit 404 may be communicably connected to BMS interface409 and/or communications interface 407 such that processing circuit 404and the various components thereof may send and receive data viainterfaces 407, 409. Processor 406 may be implemented as a generalpurpose processor, an application specific integrated circuit (ASIC),one or more field programmable gate arrays (FPGAs), a group ofprocessing components, or other suitable electronic processingcomponents.

Memory 408 (e.g., memory, memory unit, storage device, etc.) may includeone or more devices (e.g., RAM, ROM, Flash memory, hard disk storage,etc.) for storing data and/or computer code for completing orfacilitating the various processes, layers and modules described in thepresent application. Memory 408 may be or include volatile memory ornon-volatile memory. Memory 408 may include database components, objectcode components, script components, or any other type of informationstructure for supporting the various activities and informationstructures described in the present application. According to someembodiments, memory 408 is communicably connected to processor 406 viaprocessing circuit 404 and includes computer code for executing (e.g.,by processing circuit 404 and/or processor 406) one or more processesdescribed herein.

In some embodiments, BMS controller 366 is implemented within a singlecomputer (e.g., one server, one housing, etc.). In various otherembodiments BMS controller 366 may be distributed across multipleservers or computers (e.g., that may exist in distributed locations).Further, while FIG. 4 shows applications 422 and 426 as existing outsideof BMS controller 366, in some embodiments, applications 422 and 426 maybe hosted within BMS controller 366 (e.g., within memory 408).

Still referring to FIG. 4, memory 408 is shown to include an enterpriseintegration layer 410, an automated measurement and validation (AM&V)layer 412, a demand response (DR) layer 414, a fault detection anddiagnostics (FDD) layer 416, an integrated control layer 418, and abuilding subsystem integration later 420. Layers 410-420 may beconfigured to receive inputs from building subsystems 428 and other datasources, determine optimal control actions for building subsystems 428based on the inputs, generate control signals based on the optimalcontrol actions, and provide the generated control signals to buildingsubsystems 428. The following paragraphs describe some of the generalfunctions performed by each of layers 410-420 in BMS 400.

Enterprise integration layer 410 may be configured to serve clients orlocal applications with information and services to support a variety ofenterprise-level applications. For example, enterprise controlapplications 426 may be configured to provide subsystem-spanning controlto a graphical user interface (GUI) or to any number of enterprise-levelbusiness applications (e.g., accounting systems, user identificationsystems, etc.). Enterprise control applications 426 may also oralternatively be configured to provide configuration GUIs forconfiguring BMS controller 366. In yet other embodiments, enterprisecontrol applications 426 may work with layers 410-420 to optimizebuilding performance (e.g., efficiency, energy use, comfort, or safety)based on inputs received at interface 407 and/or BMS interface 409.

Building subsystem integration layer 420 may be configured to managecommunications between BMS controller 366 and building subsystems 428.For example, building subsystem integration layer 420 may receive sensordata and input signals from building subsystems 428 and provide outputdata and control signals to building subsystems 428. Building subsystemintegration layer 420 may also be configured to manage communicationsbetween building subsystems 428. Building subsystem integration layer420 translate communications (e.g., sensor data, input signals, outputsignals, etc.) across a plurality of multi-vendor/multi-protocolsystems.

Demand response layer 414 may be configured to optimize resource usage(e.g., electricity use, natural gas use, water use, etc.) and/or themonetary cost of such resource usage in response to satisfy the demandof building 10. The optimization may be based on time-of-use prices,curtailment signals, energy availability, or other data received fromutility providers, distributed energy generation systems 424, fromenergy storage 427 (e.g., hot TES 242, cold TES 244, etc.), or fromother sources. Demand response layer 414 may receive inputs from otherlayers of BMS controller 366 (e.g., building subsystem integration layer420, integrated control layer 418, etc.). The inputs received from otherlayers may include environmental or sensor inputs such as temperature,carbon dioxide levels, relative humidity levels, air quality sensoroutputs, occupancy sensor outputs, room schedules, and the like. Theinputs may also include inputs such as electrical use (e.g., expressedin kWh), thermal load measurements, pricing information, projectedpricing, smoothed pricing, curtailment signals from utilities, and thelike.

According to some embodiments, demand response layer 414 includescontrol logic for responding to the data and signals it receives. Theseresponses may include communicating with the control algorithms inintegrated control layer 418, changing control strategies, changingsetpoints, or activating/deactivating building equipment or subsystemsin a controlled manner. Demand response layer 414 may also includecontrol logic configured to determine when to utilize stored energy. Forexample, demand response layer 414 may determine to begin using energyfrom energy storage 427 just prior to the beginning of a peak use hour.

In some embodiments, demand response layer 414 includes a control moduleconfigured to actively initiate control actions (e.g., automaticallychanging setpoints) which minimize energy costs based on one or moreinputs representative of or based on demand (e.g., price, a curtailmentsignal, a demand level, etc.). In some embodiments, demand responselayer 414 uses equipment models to determine an optimal set of controlactions. The equipment models may include, for example, thermodynamicmodels describing the inputs, outputs, and/or functions performed byvarious sets of building equipment. Equipment models may representcollections of building equipment (e.g., subplants, chiller arrays,etc.) or individual devices (e.g., individual chillers, heaters, pumps,etc.).

Demand response layer 414 may further include or draw upon one or moredemand response policy definitions (e.g., databases, XML, files, etc.).The policy definitions may be edited or adjusted by a user (e.g., via agraphical user interface) so that the control actions initiated inresponse to demand inputs may be tailored for the user's application,desired comfort level, particular building equipment, or based on otherconcerns. For example, the demand response policy definitions mayspecify which equipment may be turned on or off in response toparticular demand inputs, how long a system or piece of equipment shouldbe turned off, what setpoints may be changed, what the allowable setpoint adjustment range is, how long to hold a high demand setpointbefore returning to a normally scheduled setpoint, how close to approachcapacity limits, which equipment modes to utilize, the energy transferrates (e.g., the maximum rate, an alarm rate, other rate boundaryinformation, etc.) into and out of energy storage devices (e.g., thermalstorage tanks, battery banks, etc.), and when to dispatch on-sitegeneration of energy (e.g., via fuel cells, a motor generator set,etc.).

Integrated control layer 418 may be configured to use the data input oroutput of building subsystem integration layer 420 and/or demandresponse later 414 to make control decisions. Due to the subsystemintegration provided by building subsystem integration layer 420,integrated control layer 418 may integrate control activities of thesubsystems 428 such that the subsystems 428 behave as a singleintegrated supersystem. In some embodiments, integrated control layer418 includes control logic that uses inputs and outputs from a pluralityof building subsystems to provide greater comfort and energy savingsrelative to the comfort and energy savings that separate subsystemscould provide alone. For example, integrated control layer 418 may beconfigured to use an input from a first subsystem to make anenergy-saving control decision for a second subsystem. Results of thesedecisions may be communicated back to building subsystem integrationlayer 420.

Integrated control layer 418 is shown to be logically below demandresponse layer 414. Integrated control layer 418 may be configured toenhance the effectiveness of demand response layer 414 by enablingbuilding subsystems 428 and their respective control loops to becontrolled in coordination with demand response layer 414. Thisconfiguration may advantageously reduce disruptive demand responsebehavior relative to conventional systems. For example, integratedcontrol layer 418 may be configured to assure that a demandresponse-driven upward adjustment to the setpoint for chilled watertemperature (or another component that directly or indirectly affectstemperature) does not result in an increase in fan energy (or otherenergy used to cool a space) that would result in greater total buildingenergy use than was saved at the chiller.

Integrated control layer 418 may be configured to provide feedback todemand response layer 414 so that demand response layer 414 checks thatconstraints (e.g., temperature, lighting levels, etc.) are properlymaintained even while demanded load shedding is in progress. Theconstraints may also include setpoint or sensed boundaries relating tosafety, equipment operating limits and performance, comfort, fire codes,electrical codes, energy codes, and the like. Integrated control layer418 is also logically below fault detection and diagnostics layer 416and automated measurement and validation layer 412. Integrated controllayer 418 may be configured to provide calculated inputs (e.g.,aggregations) to these higher levels based on outputs from more than onebuilding subsystem.

Automated measurement and validation (AM&V) layer 412 may be configuredto verify whether control strategies commanded by integrated controllayer 418 or demand response layer 414 are working properly (e.g., usingdata aggregated by AM&V layer 412, integrated control layer 418,building subsystem integration layer 420, FDD layer 416, or otherwise).The calculations made by AM&V layer 412 may be based on building systemenergy models and/or equipment models for individual BMS devices orsubsystems. For example, AM&V layer 412 may compare a model-predictedoutput with an actual output from building subsystems 428 to determinean accuracy of the model.

Fault detection and diagnostics (FDD) layer 416 may be configured toprovide on-going fault detection for building subsystems 428, buildingsubsystem devices (i.e., building equipment), and control algorithmsused by demand response layer 414 and integrated control layer 418. FDDlayer 416 may receive data inputs from integrated control layer 418,directly from one or more building subsystems or devices, or fromanother data source. FDD layer 416 may automatically diagnose andrespond to detected faults. The responses to detected or diagnosedfaults may include providing an alert message to a user, a maintenancescheduling system, or a control algorithm configured to attempt torepair the fault or to work-around the fault.

FDD layer 416 may be configured to output a specific identification ofthe faulty component or cause of the fault (e.g., loose damper linkage)using detailed subsystem inputs available at building subsystemintegration layer 420. In other exemplary embodiments, FDD layer 416 isconfigured to provide “fault” events to integrated control layer 418which executes control strategies and policies in response to thereceived fault events. According to some embodiments, FDD layer 416 (ora policy executed by an integrated control engine or business rulesengine) may shut-down systems or direct control activities around faultydevices or systems to reduce energy waste, extend equipment life, orassure proper control response.

FDD layer 416 may be configured to store or access a variety ofdifferent system data stores (or data points for live data). FDD layer416 may use some content of the data stores to identify faults at theequipment level (e.g., specific chiller, specific AHU, specific terminalunit, etc.) and other content to identify faults at component orsubsystem levels. For example, building subsystems 428 may generatetemporal (i.e., time-series) data indicating the performance of BMS 400and the various components thereof. The data generated by buildingsubsystems 428 may include measured or calculated values that exhibitstatistical characteristics and provide information about how thecorresponding system or process (e.g., a temperature control process, aflow control process, etc.) is performing in terms of error from its setpoint. These processes may be examined by FDD layer 416 to expose whenthe system begins to degrade in performance and alert a user to repairthe fault before it becomes more severe.

Measuring Capacitor Lifetime/Adjusting Super Capacitor Charge Voltage

Referring now to FIGS. 5-8, various systems and processes fordetermining an ideal charge voltage and adjusting a charge voltage of asuper capacitor are shown, according to some embodiments. In briefoverview, FIG. 5 shows a block diagram of an actuator that includes asuper capacitor with adjustable charge voltage. FIG. 6 is a flowchart ofa process for controlling charge voltage of a super capacitor. FIG. 7 isa flowchart of a process for determining an energy value correspondingto an actuator operation. FIG. 8 is a flowchart of a process formeasuring parameters associated with a failsafe device.

Referring particularly to FIG. 5, a block diagram of an actuator thatincludes a super capacitor with adjustable charge voltage is shown,according to some embodiments. Actuator 502 may be used to service abuilding (e.g., building 10). For example, actuator 502 may be part ofwaterside system 200. Actuator 502 may be or may be part of a failsafedevice (e.g., a device configured to fail in a specific position whenpower is removed). In some embodiments, actuator 502 is integratedwithin a building management system (e.g., BMS 400). For example,actuator 502 may send service request indications to BMS 400. Actuator502 may facilitate the reduction of aging effects in super capacitors.By reducing the effects of aging for capacitors, actuator 502 mayincrease nominal capacity and reduce the equivalent series resistance(“ESR”) of super capacitors. Therefore, the super capacitors may have anextended life cycle and charge to higher voltages later in their lifecycle.

Actuator 502 offers a number of benefits over existing actuators.Actuator 502 may be a failsafe device that includes a capacitor tofacilitate driving actuator 502 to a failsafe position in the event of afailure event (e.g., loss of power, etc.). Traditional failsafe devicestypically include a spring to facilitate return to a failsafe position.A spring limits the failsafe position to an extreme (e.g., actuatorfully extended, actuator fully retracted). Furthermore, a failsafedevice including a spring to facilitate return to a failsafe positionrequires the failsafe device to continuously fight against the action ofthe spring. For example, the failsafe device must continuously overcomethe action of the spring during normal operation, thereby requiringextra energy to power the failsafe device and making the failsafe deviceinefficient. Actuator 502 may facilitate return to a failsafe positionthat is not an extreme (e.g., in-between fully extended and fullyretracted). For example, in a three-valve scenario actuator 502 mayreturn to a failsafe position that is in the middle of the three-valve.In various embodiments, actuator 502 does not include a spring tofacilitate return to a failsafe position and therefore does not have tofight against the action of the spring, thereby increasing an efficiencyof actuator 502 over traditional failsafe devices.

Actuator 502 also offers a number of benefits over existing capacitivereturn actuators. Traditional capacitive return failsafe devices includea capacitor to facilitate return to a failsafe position. The performance(e.g., capacitance, charge time, maximum voltage rating, etc.) of acapacitor may degrade over time, thereby limiting the capacitors abilityto provide energy to drive a failsafe device to a failsafe position.Traditional capacitive return failsafe devices include an oversizedcapacitor (e.g., a super capacitor, etc.) to account for capacitorperformances losses. For example, an application requiring a 150 Faradcapacitor may include a 300 Farad capacitor as a buffer. Oversizedcapacitors may increase a size and/or cost of the failsafe device.Furthermore, traditional capacitive return failsafe devices provide noindication of the lifetime of the capacitor. For example, after twoyears of use, the capacitor in a failsafe device may have degraded tothe point that it is unable to provide the energy required to drive thefailsafe device to a failsafe position. To continue the example, thetraditional failsafe device may provide no indication of the degradedcapacitor and the user may not know that the failsafe device is unableto return to a failsafe position in a failure event.

In contrast, actuator 502 includes a capacitor to facilitate return to afailsafe position. Actuator 502 may measure the lifetime of thecapacitor and provide an indication of the lifetime to a BMS. Forexample, actuator 502 may measure the effective capacitance of thecapacitor as an indication of the lifetime of the capacitor.Furthermore, actuator 502 may measure an amount of energy required toreturn the failsafe device to a failsafe position and compare the amountof energy to the effective capacitance to determine whether thecapacitor is able to provide enough energy to return the failsafe deviceto the failsafe position. By comparing the effective capacitance to theamount of energy required to return the failsafe device to the failsafeposition, actuator 502 may extend the lifetime of the device. Forexample, a capacitor may degraded from an initial capacity of 300 Faradsto an effective capacity of 150 Farads. However, if the amount of energyrequired to return the failsafe device to the failsafe position onlyrequires an effective capacitance of 80 Farads then actuator 502 maydetermine that the capacitor is still functional, thereby prolonging thelife of the device.

In various embodiments, actuator 502 may alert a BMS that the deviceneeds to be replaced. For example, actuator 502 may determine a chargevoltage required to charge a capacitor with enough energy to return thefailsafe device to the failsafe position is too high (e.g., would causebreakdown of the capacitor) and may send an indication to a BMS thatactuator 502 and/or the capacitor should be replaced. In someembodiments, the determined charge voltage is compared to a thresholdvoltage to determine an indication of the lifetime of the capacitor. Insome embodiments, actuator 502 may determine a speed with which to drivethe failsafe device. For example, based on the measured lifetime,actuator 502 may facilitate a user to select between a first speed and asecond speed. The first speed may be associated with a first lifetime(e.g., 60 second stroke/2 years) and the second speed may be associatedwith a second lifetime (e.g., 120 second stroke/5 years).

In some embodiments, the speed to drive the failsafe device may bedynamically updated and/or selected (e.g., without user intervention)based on the determined capacitor life status. For example, actuator 502may slow down the speed with which the failsafe device is driven toprolong the life of the device. Additionally, actuator 502 may adjustthe charge voltage for the capacitor to prolong the life of thecapacitor. Actuator 502 may determine a charge voltage for the capacitorbased on comparing the effective capacitance to the energy required toreturn the failsafe device to the failsafe position. For example,actuator 502 may require a capacitance of 80 Farads at a first chargevoltage to return a failsafe device to a failsafe position, but onlyhave an effective capacitance of 60 Farads. However, actuator 502 maydetermine, based on a comparison of the amount of energy required andthe effective capacitance of the capacitor, that the amount of energyrequired may be achieved with an effective capacitance of 60 Farads at ahigher second charge voltage. Therefore, actuator 502 may charge thecapacitor at the second charge voltage. This may prolong the life of thedevice. Additionally or alternatively, actuator 502 may determine theamount of time needed to charge the capacitor. For example, actuator 502may determine an effective resistance associated with returning thefailsafe device to a failsafe position and an effective capacitance ofthe capacitor and thereby calculate the time required to charge thecapacitor. In some embodiments, actuator 502 may provide diagnosticsassociated with the operation of actuator 502. For example, actuator 502may test if the capacitor is able to provide enough energy to drive thefailsafe device to the failsafe position. Actuator 502 may provide anindication of the test (e.g., alert a user if the test fails, etc.).

Actuator 502 is shown to include capacitor 504, power supply 506,voltage regulator 514, motor 516, a resistor 517, a drive device 518,position sensors 520, communications circuit 526, and processing circuit536. In this exemplary embodiment, FIG. 5 is of actuator 502 forbuilding subsystem 428. However, in other embodiments the implementationof a super capacitor with adjustable charge voltage is used for adifferent device. In some embodiments, the device may be a deviceoutside of building subsystems 428 or within a different subsystem ofbuilding subsystem 428. For example, instead of being an actuator, thedevice may be a chiller, a boiler, a rooftop air handling unit (AHU), orother client devices.

Actuator 502 is shown to include a processing circuit 536 communicablycoupled to motor 516. In some embodiments, motor 516 is at least one ofa brushless DC (“BLDC”) motor, a DC stepper motor, a DC brushed motor,and AC brushless motor, or any type of electric motor known in the art.In some embodiments, a DC stepper motor is used for more precise motorcontrol such that the position of the motor is known. Processing circuit536 is shown to include a main actuator controller 524, memory 532, anda processor 534. Processor 534 may be a general purpose or specificpurpose processor, an application specific integrated circuit (“ASIC”),one or more field programmable gate arrays (“FPGA”), a group ofprocessing components, or other suitable processing components.Processor 534 may be configured to execute computer code or instructionsstored in memory 532 or received from other computer readable media(e.g., CDROM, network storage, a remote server, etc.).

Memory 532 may include one or more devices (e.g., memory units, memorydevices, storage devices, etc.) for storing data and/or computer codefor completing and/or facilitating the various processes described inthe present disclosure. Memory 532 may include random access memory(“RAM”), read-only memory (“ROM”), hard drive storage, temporarystorage, non-volatile memory, flash memory, optical memory, or any othersuitable memory for storing software objects and/or computerinstructions. Memory 532 may include database components, object codecomponents, script components, or any other type of informationstructure for supporting the various activities and informationstructures described in the present disclosure. Memory 532 may becommunicably connected to processor 534 via processing circuit 536 andmay include computer code for executing (e.g., by processor 534) one ormore processes described herein. When processor 534 executesinstructions stored in memory 532, processor 534 generally configuresactuator 502 (and more particularly processing circuit 536) to completesuch activities.

Main actuator controller 524 may be configured to receive externalcontrol data 530 (e.g., position setpoints, speed setpoints, etc.) fromcommunications circuit 526 and position signals 522 from positionsensors 520. Main actuator controller 524 may be configured to determinethe position of motor 516 and/or drive device 518 based on positionsignals 522. In some embodiments, main actuator controller 524 receivesdata from additional sources. For example, main actuator controller 524may receive information from sensors (e.g., temperature sensors,humidity sensors, etc.) within building subsystems 428, as described indetail with reference to FIG. 4.

Motor 516 may be coupled to drive device 518. Drive device 518 may be adrive mechanism, a hub, or other device configured to drive oreffectuate movement of a HVAC system component (e.g., equipment 538).For example, drive device may be configured to receive a shaft of adamper, a valve, or any other movable HVAC system component in order todrive (e.g., rotate) the shaft. In some embodiments, actuator 502includes a coupling device configured to aid in coupling drive device518 to the movable HVAC system component. For example, the couplingdevice may facilitate attaching drive device 518 to a valve or dampershaft.

The resistor(s) 517 may be in series or in parallel with the capacitor504 (e.g., in the same branch as the capacitor 504) and may be any typeof resistor including a shunt resistor. In some embodiments, theresistor 517 may comprise multiple resistors in the same branch as thecapacitor 504. In some embodiments, the resistor 517 may be a shuntresistor configured to drop the output voltage of the capacitor 504 to apredefined input voltage of the motor 516. In some embodiments, theactuator 502 may include a voltage sensor proximate or at the resistor517 such that the voltage sensor can sense the voltage drop across theresistor 517. Using the known resistance of the resistor 517 and thevoltage drop across the resistor 517, current may be determined (e.g.,Current (i)=Voltage (V)/Resistance (R)).

Position sensors 520 may include Hall effect sensors, potentiometers,optical sensors, a step counter, an internal time, a backelectromagnetic frequency (EMF) sensor, or other types of sensorsconfigured to measure the rotational position of the motor 516 and/ordrive device 518. Position sensors 520 may provide position signals 522to processing circuit 536. Main actuator controller 524 may use positionsignals 522 to determine whether to operate the motor 516. For example,main actuator controller 524 may compare the current position of drivedevice 518 with a position setpoint received via external data input 530and may operate the motor 516 to achieve the position setpoint. In someembodiments, positions sensors 520 may be a step counter that receivesan indication of the step of the motor 516 or a back EMF sensor thatdetermines the back EMF of the motor 516 and calculates a position ofthe motor 516 or the drive devices 518. By using a step counter or anback EMF sensor, the positon of the motor 516 can be better determinedand provided to the main actuator controller 524.

Actuator 502 is further shown to include a communications circuit 526.Communications circuit 526 may be a wired or wireless communicationslink and may use any of a variety of disparate communications protocols(e.g., BACnet, LON, WiFi, Bluetooth, NFC, TCP/IP, etc.). In someembodiments, communications circuit 526 is a circuit configured tooutput or provide analog communications. For example, communicationscircuit 526 may provide communications and information regarding theactuator 502 using one or more of pulse width modulated (PWM) wavesignals, a saw tooth signal, or any other type of analog signals. Insome embodiments, communications circuit 526 may include any requiredanalog to digital converter or digital to analog converter to transformany signals. The analog signal can drive light warnings or audiblewarnings of life of the capacitor 504. In some embodiments,communications circuit 526 is an integrated circuit, chip, ormicrocontroller unit (“MCU”) configured to bridge communicationsactuator 502 and external systems or devices. In some embodiments,communications circuit 526 is the Johnson Controls BACnet on a Chip(“JBOC”) product. For example, communications circuit 526 may be apre-certified BACnet communication module capable of communicating on abuilding automation and controls network (BACnet) using a master/slavetoken passing (“MSTP”) protocol. Communications circuit 526 may be addedto any existing product to enable BACnet communication with minimalsoftware and hardware design effort. In other words, communicationscircuit 526 provides a BACnet interface for actuator 502. Furtherdetails regarding the JBOC product are disclosed in U.S. patentapplication Ser. No. 15/207,431 filed Jul. 11, 2016, the entiredisclosure of which is incorporated by reference herein.

Communications circuit 526 may also be configured to support datacommunications within actuator 502. In some embodiments, communicationscircuit 526 may receive internal actuator data 528 from main actuatorcontroller 524. For example, internal actuator data 528 may include ameasured or calculated motor torque, the actuator position or speed,configuration parameters, end stop locations, stroke length parameters,commissioning data, equipment model data, firmware versions, softwareversions, time series data, a cumulative number of stop/start commands,a total distance traveled, an amount of time required to open/closeequipment 538 (e.g., a valve), or any other type of data used or storedinternally within actuator 502. In some embodiments, communicationscircuit 526 may transmit external data 530 to main actuator controller524. External data 530 may include, for example, position setpoints,speed setpoints, control signals, configuration parameters, end stoplocations, stroke length parameters, commissioning data, equipment modeldata, actuator firmware, actuator software, or any other type of datawhich may be used by actuator 502 to operate the motor 516 and/or drivedevice 518.

In some embodiments, external data 530 is a DC voltage control signal.Actuator 502 may be a linear proportional actuator configured to controlthe position of drive device 518 according to the value of the DCvoltage received. For example, a minimum input voltage (e.g., 0.0 VDC)may correspond to a minimum rotational position of drive device 518(e.g., 0 degrees, −5 degrees, etc.), whereas a maximum input voltage(e.g., 10.0 VDC) may correspond to a maximum rotational position ofdrive device 518 (e.g., 90 degrees, 95 degrees, etc.). Input voltagesbetween the minimum and maximum input voltages may cause actuator 502 tomove drive device 518 into an intermediate position between the minimumrotational position and the maximum rotational position. In otherembodiments, actuator 502 may be a non-linear actuator or may usedifferent input voltage ranges or a different type of input controlsignal (e.g., AC voltage or current) to control the position and/orrotational speed of drive device 518.

In some embodiments, external data 530 is an AC voltage control signal.Communications circuit 526 may be configured to transmit an AC voltagesignal having a standard power line voltage (e.g., 120 VAC or 230 VAC at50/60 Hz). The frequency of the voltage signal may be modulated (e.g.,by main actuator controller 524) to adjust the rotational positionand/or speed of drive device 518. In some embodiments, actuator 502 usesthe voltage signal to power various components of actuator 502. Actuator502 may use the AC voltage signal received via communications circuit526 as a control signal, a source of electric power, or both. In someembodiments, the voltage signal is received from a power supply linethat provides actuator 502 with an AC voltage having a constant orsubstantially constant frequency (e.g., 120 VAC or 230 VAC at 50 Hz or60 Hz). Communications circuit 526 may include one or more dataconnections (separate from the power supply line) through which actuator502 receives control signals from a controller or another actuator(e.g., 0-10 VDC control signals).

In some embodiments, actuator 502 is an actuator in building subsystems428. Alternatively, actuator 502 may be outside of building subsystems428 (not shown). Actuator 502 may be configured to be connected tocapacitor 504 and powered by capacitor 504. Actuator 502 may consumeelectricity from an electric utility and may also be powered by powersupply 506. The initial position (P_(i)) of actuator 502 and the finalposition (P_(f)) of actuator 502 may be input to memory 532. The initialposition (P_(i)) of actuator 502 may be the position of actuator 502when processor 534 first receives a signal that power is lost toactuator 502 from power supply 506 (e.g., a first indication of nopower). The final position (P_(f)) of actuator 502 may be the positionof actuator 502 (e.g., an actuator) when actuator 502 returns to adefault position.

In some embodiments, capacitor 504 is configured to provide a processor(e.g., processor 534) with the values of voltages across capacitor 504at various times. For example, processor 534 may be configured tomeasure the value of an initial voltage (V_(i)), across capacitor 504 atthe time when actuator 502 is in position P_(i), the value of a finalvoltage (V_(f)) across capacitor 504 at the time when actuator 502 is inposition P_(f), the value of a first voltage (V₁) across capacitor 504at a first specified time t₁, and/or the value of a second voltage (V₂)across capacitor 504 at a second specified time t₂. In some embodiments,the difference between the first time (t₁) and the second time (t₂) is apredetermined time. Voltage readings (e.g., V_(i), V_(f), V₁, V₂) may beinput to non-volatile memory (e.g., memory 532) to be used incalculations to determine capacitance (C), energy used by actuator 502to return to its default position (W_(r)), and/or charge voltage(V_(c)). In some embodiments, capacitor 504 is an electrostaticdouble-layer capacitor (“EDLC”) super capacitor that is charged by powersupply 506. Power supply 506 may also be configured to power actuator502. Alternatively, more than one power supply may be configured topower actuator 502 and/or capacitor 504.

In some embodiments, capacitor 504 transmits diagnostic information. Forexample, actuator 502 may test that capacitor 504 has enough energy toreturn a failsafe device (e.g., drive motor 516) to a failsafe positionand report upon the test. In some embodiments, the test may occurperiodically (e.g., every time actuator 502 is powered down, etc.). Forexample, upon power down, capacitor 504 may power motor 516 to movedrive device 518 to a failsafe position and position sensors 520 maydetermine if capacitor 504 was able to do so. In response, actuator 502may provide diagnostic information to a user and/or BMS controller 366.In some embodiments, the diagnostic information may indicate thatcapacitor 504 and/or actuator 502 need to be replaced. In someembodiments, actuator 502 includes a sensor 507 in line with powersupply 506, for measuring the current and/or voltage provided by powersupply 506, which can be used to determine the energy provide toactuator 502, and thereby the energy consumption of actuator 502.Accordingly, sensor 507 may be any suitable sensor for measuringcurrent, voltage, or energy consumption, such as a Hall effect sensor.

In some embodiments, the actuator 502 may provide a visual indication ofany diagnostic information (e.g., via a diagnostic LED 542). Thediagnostic LED 542 may be communicably coupled to the main actuatorcontroller 524 and receive an indication of the diagnostic status of thecapacitor 504 and/or the actuator 502. Furthermore, the diagnostic LED542 may then be illuminated in a specific diagnostic color. For example,the diagnostic LED 542 may light up specially as: red=maintenance needed(e.g., change capacitor 504 immediately), yellow=maintenance needed soon(e.g., change capacitor soon), and green=no maintenance needed (e.g.,capacitor is working correctly). In some embodiments, the diagnostic LED542 may light up at a certain frequency (e.g., blink) or following acertain pattern to provide an indication of the status of the actuator502. This may provide an indication to workers working near the actuator502 of the status of the actuator 502 or the capacitor 504.

Still referring to FIG. 5, memory 534 may be configured to store variousmodules that may calculate the charge voltage (V_(c)) (i.e., a maximumvoltage level that may be used to charge the super capacitor). In thisexemplary embodiment, memory 534 is shown to include main actuatorcontroller 524, capacitance module 508, energy module 510, and chargevoltage module 512. However, in some embodiments memory 534 includesmore modules and/or excludes one or more of the modules shown in FIG. 5.For example, memory 534 may include one module that completes bothcalculations performed by energy module 510 and capacitance module 508.

In some embodiments, capacitance module 508 is configured to determine acapacitance (C) of a super capacitor (e.g., capacitor 504). In someembodiments, capacitance module 508 receives inputs from memory 534. Theinputs may correspond to the voltage measured across the super capacitoror across the super capacitor branch as described herein at time t₁ andthe voltage measured across the super capacitor or across the supercapacitor branch as described herein at time t₂; voltages V₁ and V₂respectively. Using these voltage readings as well as a safety factor(S), capacitance module 508 may determine the capacitance of the supercapacitor using Equation 1:

$\begin{matrix}{C = {S\frac{\left( {V_{1} - V_{2}} \right)}{\left( {t_{1} - t_{2}} \right)}}} & (1)\end{matrix}$

In some embodiments, the difference between t₁ and t₂ is a predeterminedlength of time. Advantageously, this may ensure that the time betweeneach voltage measurement is consistent for calculating the capacitancefor each power cycle of the power supply. In other embodiments, thedifference between t₁ and t₂ may be variable and may depend on aspecific voltage threshold of V₁ or V₂. In some embodiments, capacitancemodule 508 outputs the determined capacitance (C) to energy module 510and charge voltage module 512 to be used in other calculations. In someembodiments, the safety factor (S), may be included to provide a factorof safety into equation 1 and may be any value including 1, <1 (e.g.,0.4, 0.6, 0.8, 0.9, etc.) or >1 (e.g., 1.1, 1.2, 1.3, 1.4, 1.5, etc.).

In some embodiments, capacitance module 508 is configured to determine acapacitance (C) of a super capacitor (e.g., capacitor 504) using anotherformula. In some embodiments, capacitance module 508 receives inputsfrom memory 534. The inputs may correspond to a current across aresistor in series with the super capacitor (e.g., the resistor 517) andthe voltage measured across the super capacitor the super capacitorbranch as described herein at time t₁ and the voltage measured acrossthe super capacitor or across the super capacitor branch as describedherein at time t₂; currents i₁ and i₂, respectfully and voltages V₁ andV₂, respectively. In some embodiments, current across the resistor 517is determined using by determining voltage drop across the resistor aswell the known resistance value of the resistor 517 (i.e., i=V/R). Usingthese voltage readings and current readings as well as a safety factor(S), capacitance module 508 may determine the capacitance of the supercapacitor using Equation 2:

$\begin{matrix}{C = {S{\int_{t_{1}}^{t_{2}}\frac{\left( {i_{1} - i_{2}} \right)}{\left( {V_{1} - V_{2}} \right)}}}} & (2)\end{matrix}$

In some embodiments, the difference between t₁ and t₂ is a predeterminedlength of time. In other embodiments, the difference between t₁ and t₂may be variable and may depend on a specific voltage threshold of V₁ orV₂. In some embodiments, capacitance module 508 outputs the determinedcapacitance (C) to energy module 510 and charge voltage module 512 to beused in other calculations. In some embodiments, the safety factor (S)is the same value as the safety factor of Equation 1. In otherembodiments, the safety factor (S) is the a different value as thesafety factor of Equation 1. As described herein, the determinedcapacitance (C) may be determined using Equation 1 or Equation 2.

In some embodiments, capacitance module 508 is configured to determinethe residual life of the super capacitor by measuring a residual liferatio (RL) for the capacitor over an average number of charges (e.g., 10charges). For example, the capacitance module 508 may receive inputsfrom memory 534. The inputs may correspond to the voltage measuredacross the super capacitor at time t₁ and the voltage measured acrossthe super capacitor at time t₂; voltages V₁ and V₂ respectively. In someembodiments, t₁ is the time the super capacitor began charging and timet₂ is the time the super capacitor was fully charged. Using thesevoltage readings, for multiple different charging events, capacitancemodule 508 may determine the average capacitance during n initial (e.g.,the first 10) chargings (e.g., power cycles of the power supply) of thesuper capacitor (C _(i)), and the average capacitance during another n(e.g., the 50^(th)-60^(th)) chargings of the super capacitor (C_(k) ),where capacitance is determined as described as described with respectto Equation 1 or Equation 2 and herein, and calculate the RL usingEquations 3, 4, and 5:

$\begin{matrix}{{\overset{\_}{C}}_{l} = \frac{\sum_{t = 1}^{n}C_{t}}{n}} & (3) \\{\overset{\_}{C_{k}} = \frac{\sum_{t = k}^{k + n}C_{t}}{n}} & (4) \\{{RL} = \frac{\overset{\_}{C_{k}}}{{\overset{\_}{C}}_{l}}} & (5)\end{matrix}$

In some embodiments, a residual life ratio (RL) of 0.85 may indicatethat the super capacitor has begun failing and may soon requirereplacement. In other embodiments, a RL of 0.82 may indicate that thesuper capacitor has failed and requires replacement. The RL ratio may beused as described herein to provide an indication of the life left inthe super capacitor. In some embodiments, the RL ratio may be used todetermine if the super capacitor should be replaced and may be providedto the various components of the BMS controller 366 or the clientdevices 448 to provide a warning or indication of super capacitor life.

In some embodiments, energy module 510 is configured to determine theenergy value (W_(r)) used for a device (e.g., actuator 502) to return toa default position after losing power. Additionally, the calculation ofW_(r) may be stored in non-volatile memory (e.g., memory 532). AfterW_(r) is determined by energy module 510, the value of W_(r) may beoutput to charge voltage module 512. In some embodiments, energy module510 calculates W_(r) by taking the difference between two values ofenergy, initial energy W_(i) and final energy W_(f). W_(i), W_(f), andW_(r) is determined using Equation 6, Equation 7, and Equation 8,respectively:

W _(i)=½CV _(i) ²  (6)

W _(f)=½CV _(f) ²  (7)

W _(r) =S(W _(i) −W _(f))  (8)

where C is the calculated capacitance from capacitance module 508, V_(i)is the voltage across the super capacitor when actuator 502 is at aninitial position P_(i), V_(f) is the voltage across the super capacitorwhen actuator 502 is at a final position P_(f), and S is a safety factorwhich may or may not be equal to the safety factor of Equations 1 and 2.

In some embodiments, charge voltage module 512 is configured todetermine the charge voltage (V_(c)) (i.e., a maximum voltage level thatmay be used to charge the super capacitor). For example, charge voltagemodule 512 calculates V_(c) and outputs voltage data to voltageregulator 514 in order to regulate capacitor 504. In some embodiments,charge voltage module 512 receives inputs from capacitance module 508and energy module 510 within memory 532 that include values forcapacitance (C) and energy value (W_(r)), respectively. Using thepreviously determined values of C and W_(r), charge voltage module 512may calculate the value of charge voltage using Equation 9:

$\begin{matrix}{V_{c} = {S\sqrt{\frac{2W_{r}}{C}}}} & (9)\end{matrix}$

where W_(r) is the energy used to return the device to a defaultposition after power is lost and C is the capacitance of the supercapacitor and S is a safety factor which may or may not be the same asthe safety factor of Equations 1, 2, and 8. After completion ofcalculating charge voltage, charge voltage module 512 may be configuredto output the determined value of charge voltage as voltage data tovoltage regulator 514.

Voltage regulator 514 may be configured to control charge voltage(V_(c)). In some embodiments, voltage regulator 514 takes the form of apotentiometer configured to control V_(c) by changing the feedbackresistance of a power supply for each power cycle of the power supply.However, in other embodiments the voltage regulator may take the form ofa digital to analog converter configured to control V_(c) by changingthe feedback resistance attached to a regulator feedback pin for eachpower cycle of the power supply. In yet other embodiments the voltageregulator may take the form of a silicon controlled rectifier configuredto control V_(c) by changing a feedback resistance of a power supply foreach power cycle of the power supply. In still other embodiments thevoltage regulator may take the form of an adjustable power supply outputconfigured to control V_(c) by a variable output adjusted for each powercycle of the power supply. When actuator 502 is first powered on,processor 534 may initialize V_(c) to a rated voltage for capacitor 504.In some embodiments, the calculated V_(c) is input as voltage data tovoltage regulator 514 from charge voltage module 512 for every cycle ofthe power supply.

In some embodiments, voltage regulator 514 includes a boost-bucktopology or other similar devices that combines a step-up converter witha step-down converter, or that increases/decreases an input voltage.Specifically, in such embodiments, voltage regulator 514 includes adiscrete boost-buck topology, as shown in detail in FIG. 11. Forexample, voltage regulator 514 may include a plurality of components(e.g., MOSFETs, transistors, resistors, etc.) to step-up (i.e.,increase) or step-down (i.e., decrease) the voltage supplied tocapacitor 504 (e.g., V_(c)). However, in other embodiments, theboost-buck topology described herein can be included in power supply506, or may be a separate component of actuator 502, shown as boost-buckconverter 515. In some embodiments, boost-buck converter 515, may becontrolled by processing circuit 536, or by another controller (e.g., amicrocontroller). In some embodiments, the topology of boost-buckconverter 515 may be changed to either charge or deplete capacitor 506,as described in greater detail below with respect to FIG. 11.

In some embodiments, memory 532 further includes an artificialintelligence (AI) module 540. AI module 540 may be communicably coupledwith the other modules or components of the memory as well as the mainactuator controller 524 and may be configured to optimize the life ofthe capacitor 504 by implementing a machine learning algorithm tocorrelate one or more variables (e.g., V_(c), W_(f). W_(i), W_(f), etc.)to the life of the capacitor 504 (e.g., keep the RL near or equal to 1).In some embodiments, the AI module 540 may implement a model (e.g., alinear regression model, a logistic regression model, a Naïve Bayesclassifier, a clustering model, etc.) to correlate the various variablesdescribed herein and instruct the main actuator controller 524 toimplement one or more different values. In one example, the AI module540 may correlate the control charge voltage of the voltage regulator514 to the life of the capacitor 504 and therefore determine an optimalcontrol charge voltage to be applied to the capacitor 504 at variouspoints in time. In another example, the AI module 540 may determine anoptimal initial and final energy of the actuator 502 to reach an optimallifetime of the capacitor 504 to then provide the optimal initial andfinal energy of the actuator to the main actuator controller 524.

Now referring to FIG. 6, a flowchart of a process for controlling chargevoltage of a super capacitor is shown, according to some embodiments.Process 600 may be configured to repeat for each power cycle of a powersupply for the device. By continually controlling the charge voltage ofa super capacitor to equal that of a minimum required operating voltage,process 600 allows the super capacitor to charge at lower voltages nearthe beginning of the life cycle of the super capacitor, reducing theaging effect of the capacitor. The super capacitor may then charge tohigher voltages later in the life cycle of the super capacitor to offsetcapacitance reduction because of the aging effect. In some embodiments,process 600 is performed by various components of memory 532. In otherembodiments, process 600 is completed by components outside of memory532, such as by a controller outside of actuator 502.

Process 600 is shown to include measuring a first voltage across a supercapacitor (step 602). The first voltage (V₁) may be measured across thesuper capacitor (e.g., capacitor 504) by processor 534 within processingcircuit 536 at a time t₁. Time t₁ may be a predetermined value thatoccurs a certain amount of time before a second time t₂. For example,time t₁ may occur one minute before time t₂. Measurement V₁ may be inputback into memory (e.g., memory 532) to be used in calculatingcapacitance (C) in capacitance module 508.

Process 600 is shown to include measuring a second voltage across thesuper capacitor (step 604). The second voltage (V₂) may be measuredacross the super capacitor (e.g., capacitor 504) by processor 534 at asecond specific time t₂. Time t₂ may be predetermined by processor 534to be a specific amount of time after the first time t₁. Voltagemeasurement V₂ may be input into non-volatile memory (e.g., memory 532)in order to calculate capacitance (C) in capacitance module 508. In someembodiments, steps 602-604 include discharging the capacitor through aknow load. Additionally or alternatively, steps 602-604 may includedetermining an output current of the capacitor based on the dischargethrough a known load. In various embodiments, the output current of thecapacitor may be used to determine the effective capacitance of thecapacitor.

Process 600 is shown to include calculating a capacitance using thefirst and second voltages (step 606). In some embodiments, step 606 isaccomplished by an equation stored within capacitance module 508 inmemory. Once the values of the first and second voltages are measuredand stored in memory, capacitance module 508 may determine thecapacitance (C) with an equation saved in memory as well. The equationapplied for capacitance may be the same as Equation 1 or Equation 2,described more in detail with reference to FIG. 5.

Process 600 is shown to include calculating a charge voltage using thecalculated capacitance (step 608). The calculated capacitance may be thecapacitance determined in step 606. In some embodiments, charge voltagemodule 512 completes step 608 using an equation stored within memory(e.g., memory 532) to determine the charge voltage. The charge voltage(V_(c)) is calculated to be a minimum required operating voltage thatensures proper operation of the failsafe return. The failsafe return foran actuator, for example, is that the actuator returns to a defaultposition when a loss of power is endured. Applying the minimum requiredoperating voltage to the super capacitor reduces the aging effect of thecapacitor and extends the life cycle of the super capacitor. Theequation applied to determine charge voltage may be Equation 9,described with reference to FIG. 5, where W_(r) is the calculated energyvalue used by the actuator to return to the default position and C isthe calculated capacitance. In some embodiments, step 608 includescomparing the calculated capacitance to an amount of energy required forthe failsafe return. For example, process 600 may include measuring theamount of energy required to drive an actuator from a first position toa failsafe position and comparing the measured amount of energy to aneffective capacitance of the capacitor to determine a charge voltage forthe capacitor. In some embodiments, process 600 may include sending anindication of the lifetime of the capacitor to a BMS. For example,process 600 may include determining a charge voltage for the capacitoras described in the example above, comparing the charge voltage to abreakdown voltage of the capacitor, and sending an indication to the BMSof the lifetime of the device based on the comparison. In someembodiments, the indication of the lifetime of the capacitor mayindicate that the capacitor needs to be replaced.

Process 600 is shown to include applying the charge voltage (V_(c)) tothe super capacitor (step 610). After step 608 has completed and thecharge voltage has been determined, step 610 may be completed by chargevoltage module 512 in memory and a voltage regulator (e.g., voltageregulator 514 described with reference to FIG. 5). In some embodiments,processor 534 passes on the value of the charge voltage as voltage datafrom memory to voltage regulator 514 via communications circuit 526,described in detail with reference to FIG. 5. Processor 534 then sets afinal charging voltage of the capacitor for the power cycle of powersupply 506 to the calculated V_(c). The final charging voltage of thesuper capacitor may be controlled by regulation of power supply 506 forthe capacitor via voltage regulator 514.

In some embodiments, capacitor 504 is full charged upon initializationor power-up, such as to guarantee that capacitor 504 can provide anadequate amount of energy in case of a failsafe event. For example,capacitor 504 may be initially charged to a maximum value, rather than aminimum required operating voltage, to ensure adequate available energy.In such embodiments, capacitor 504 may be allowed to slowly reach theminimum required operating voltage via leakage current. In other words,capacitor 504 may be allowed to slowly leak current over time to reachthe desired minimum required operating voltage. In other embodiments,energy may be dissipated via a shunt or limiting resistor (e.g.,resistor(s) 517) in order to lower a fully-charged capacitor 504 to thedesire minimum required operating voltage.

Referring now to FIG. 7, a flowchart of a process 700 for determining anenergy value corresponding to an actuator operation is shown, accordingto some embodiments. Process 700 may be configured to repeat for eachpower cycle of power supply 506 to actuator 502. In order to ensure thatactuator 502 returns to a default position when power is lost, an amountof energy consumed for actuator 502 to return to the default position iscalculated. The calculated value of energy consumed is then used todetermine a minimum required operating voltage. In some embodiments,process 700 is used to calculate the energy value used in step 608 ofprocess 600, described in detail with reference to FIG. 6. Process 700may be performed by various components within memory 532. In someembodiments, one or more steps of process 700 is performed by componentsoutside of memory 532.

Process 700 is shown to include checking if an actuator has power ordoes not have power (step 702). If processor 534 determines in step 702that the actuator is powered, process 700 is shown to proceed withmeasuring an initial voltage across the super capacitor (step 704). Theinitial voltage (V_(i)) may be measured by the processor (e.g.,processor 534) within the BMS controller to correspond with the voltageacross the super capacitor when actuator 502 is at an initial positionP_(i). For example, the initial position P_(i) is a position of actuator502 when processor 534 first receives a signal that actuator 502 haslost power. However, if during step 702 processor 534 determines thatactuator 502 is not powered, process 700 is shown to proceed withrepeating to check if actuator 502 is powered (step 702).

Process 700 is shown to include calculating an initial energy value(step 706). In some embodiments, step 706 is completed by energy module510 within memory (e.g., memory 532). In some embodiments, energy module510 receives inputs from capacitance module 508 of the calculatedcapacitance (C) and the initial voltage (V_(i)) measured across thesuper capacitor (e.g., capacitor 504) in step 704. The initial energyvalue may be determined by an equation stored in energy module 510. Forexample, the equation applied to calculate the initial energy value maybe the same as Equation 6, described in detail with reference to FIG. 5.

In some embodiments, rather than measure an initial voltage (V_(i))across the super capacitor, the initial energy value is determined bymeasuring a voltage across one of the other components of actuator 502and calculating the component's energy consumption. In particular, theenergy consumption of resistor(s) 517, motor 516, or any of the othercomponents may be measured and/or calculated. For example, energyconsumption of motor 516 could be measured through a shunt resistor(e.g., resistor 517). Based on the energy consumption of motor 516, thepower consumption of the remaining components of actuator 502 may beassumed as constant values.

Process 700 is shown to include checking if the actuator is in defaultposition (step 708). If processor 534 determines in step 708 thatactuator 502 is not in default position, process 700 is shown to proceedwith continuing to check if actuator 502 is in default position (step708). However, if processor 534 determines in step 708 that actuator 502is in default position, process 700 is shown to proceed with measuring afinal voltage across the super capacitor (step 710). In someembodiments, final voltage (V_(f)) is measured by processor 534 to be avalue of the voltage across the super capacitor (e.g., capacitor 504)when actuator 502 is at a final position (P_(f)). For example, the finalposition is the position of actuator 502 when actuator 502 has returnedto the default position. In various embodiments, the default position iswithin the range of the actuator 502 (e.g., actuator 502 is in betweenfully extended and fully retracted, in the middle, etc.).

Process 700 is shown to include calculating a final energy value (step712). In some embodiments, step 712 is completed by energy module 510within memory (e.g., memory 532). In some embodiments, energy module 510receives input from capacitance module 508 of the capacitance (C)calculated in step 606 of process 600 and input from memory 532 of thevalue of the final voltage (V_(f)) measured across the super capacitor(e.g., capacitor 504) in step 710. The final energy value (W_(f)) may bedetermined by an equation stored in energy module 510. For example, theequation applied to determine the final energy value may be the same asEquation 7, described in detail with reference to FIG. 5.

In some embodiments, rather than measure a final voltage (V_(f)) acrossthe super capacitor, the initial energy value is determined by measuringa voltage across one of the other components of actuator 502 andcalculating the component's energy consumption, similar to calculatingthe initial voltage at step 706. In particular, the energy consumptionof resistor(s) 517, motor 516, or any of the other components may bemeasured and/or calculated. For example, energy consumption of motor 516could be measured through a shunt resistor (e.g., resistor 517). Basedon the energy consumption of motor 516, the power consumption of theremaining components of actuator 502 may be assumed as constant values.

In some embodiments, the initial voltage and/or final voltage aredetermined based on the overall energy consumption of actuator 502. Forexample, the total energy consumption of actuator 502 can be determinedas described above, or by measuring the energy consumption via sensor507, either before or after power supply 506. In other words, sensor 507may be utilized to determine how much energy actuator 502 is consumingin total.

Process 700 is shown to include calculating an energy value usinginitial and final energy values (step 714). In some embodiments, step714 is also be completed by energy module 510 within memory. Using bothcalculated values of the initial energy value (W_(i)) and the finalenergy (W_(f)) value from steps 706 and 712 respectively, energy module510 may determine the energy value (W_(r)) by applying an equationstored in non-volatile memory (e.g., memory 532). For example, theequation applied to determine the energy value that uses both theinitial and final energy values may be the same as Equation 8, describedin detail with reference to FIG. 5. In some embodiments, the differencebetween the initial energy value and final energy value calculates theamount of energy consumed for the actuator (e.g., actuator 502) toreturn to its default position. In other embodiments, energy value W_(r)is determined by taking the absolute value of the initial energy valuesubtracted from the final energy value.

As described above, process 700 may be performed by measuring a voltageacross capacitor 504 when actuator 502 is in various positions. Thuscertain portions of process 700 may require charging and discharging ofcapacitor 504. However, in some embodiments, certain steps of process700 can be performed without discharging capacitor 504, by performingprocess 700 and/or a failsafe action using power supply 506 andaccording to the failsafe routine described herein. In this manner, thecharge of capacitor 504 may be maintained, and the lifespan of capacitor504 may be extended by reducing the need to charge/discharge capacitor504 for testing or determining the energy requirements for failsafe. Inother embodiments, rather than implementing process 700, the energyrequired for failsafe action may be a constant related to the overallstroke of actuator 502 and/or the time required to perform the failsafeaction/movement.

Referring now to FIG. 8, a flowchart of a process 800 for determiningparameters associated with a failsafe device is shown, according to someembodiments. Process 800 may be configured to repeat for each powercycle of power supply 506 to actuator 502. Additionally oralternatively, process 800 may repeat at scheduled intervals (e.g.,every month, etc.). In some embodiments, the results of process 800 arestored in memory for later use (e.g., for calculating lifetime trends ofactuator 502, etc.). In various embodiments, process 800 is used tocalculate the values used in process 900 and 1000, as described indetail below. Process 800 may be performed by various components withinmemory 532. In some embodiments, one or more steps of process 800 areperformed by components outside of memory 532.

Process 800 is shown to include measuring an amount of energy requiredto return a failsafe device to a failsafe position (step 810). In someembodiments, actuator 502 is the failsafe device. Additionally oralternatively, the failsafe device may be any device configured toreturn to a failsafe position upon failure (e.g., removal of power,etc.). The failsafe position may be a specific position within the rangeof movement of the failsafe device. For example, a linear actuator mayfail to a midway point between fully extended and fully retracted. Insome embodiments, the failsafe position is determined dynamically (e.g.,in response to a failure type, etc.). In some embodiments, step 810 isperformed according to methods disclosed above in reference to FIG. 5.Additionally or alternatively, step 810 may be performed according tosteps 812-816.

At step 812, actuator 502 positions the failsafe device in a firstposition. For example, motor 516 may drive drive device 518 to apositional extreme (e.g., fully extended, fully retracted, etc.). Atstep 814, actuator 502 measures the current (I) and voltage (V)associated with driving the failsafe device to the failsafe position.For example, motor 516 may drive drive device 518 to a specific position(e.g., midway between fully extended and fully retracted, etc.) andmeasure the associated voltage and current. In some embodiments, energymodule 510 calculates (step 816) the amount of energy required to returnthe failsafe device to the failsafe position using Equation 10 andEquation 11:

W=V*I  (1)

J=S*W*s  (11)

where s is the time associated with driving the failsafe device to thefailsafe position J is the amount of energy required, and S is a safetyfactor which may or may not be the same as the safety factor ofEquations 1, 2, 8, and 9. In various embodiments, the amount of energyrequired (J) is stored in memory for later use.

At step 820, actuator 502 measures an effective capacitance of thecapacitor (e.g., capacitor 504). In some embodiments, step 820 isperformed according to methods disclosed above in reference to FIG. 5.Additionally or alternatively, step 820 may be performed according tosteps 822-832. At step 822, the capacitor (e.g., capacitor 504) ischarged to full. In some embodiments, the capacitor may be charged to adifferent level (e.g., half-charged, etc.). At step 824, capacitancemodule 508 may measure a first voltage of the capacitor. At step 826,the capacitor is discharged through a known load (e.g., a fixedresistance, etc.). At step 828, capacitance module 508 may measure acurrent associated with the discharge. At step 830, capacitance module508 may measure a second voltage of the capacitor. At step 832,capacitance module 832 determines, based on the previously measuredvalues, the effective capacitance of the capacitor. In some embodiments,capacitance module 508 calculates the effective capacitance of thecapacitor via the time constant (τ) using Equations 12 and/or Equation13:

V _(c) =S*V ₀ e ^(t/RC)  (12)

τ=S*RC  (13)

where V_(c) is the voltage across the capacitor after time t, V₀ is theinitial voltage across the capacitor, R is the known resistance, τ isthe time constant of the circuit corresponding to the time required tocharge the capacitor from an initial voltage of zero to approximately63.2% of the value of an applied DC source (alternatively, the timeconstant may correspond to the time required to discharge the capacitorfrom full charge to 36.8% of full charge), and S is a safety factorwhich may or may not be the same as the safety factor of equations 1, 2,8, 9, and 11.

Referring now to FIG. 9A, a flowchart of a process 900 for determining alifetime of a capacitor is shown, according to some embodiments. Process900 may be configured to repeat for each power cycle of power supply 506to actuator 502. Additionally or alternatively, process 900 may repeatat scheduled intervals (e.g., every week, etc.). In some embodiments,the results of process 900 are stored in memory (e.g., for calculatinglifetime trends of actuator 502, etc.). In various embodiments, process900 uses the values from process 800. Process 900 may be performed byvarious components within memory 532. In some embodiments, one or moresteps of process 900 are performed by components outside of memory 532.In various embodiments, process 900 may determine a remainingoperational period for capacitor 504 and send an indication of theoperational period. The operational period corresponds to the length oftime capacitor 504 is capable of storing the amount of energy requiredto return a failsafe device to a failsafe position. This may allowbuilding operators to replace defective failsafe devices/capacitorsbefore they become non-functional. Furthermore, it may reduce and/oreliminate a need to manually test failsafe devices for operability andtherefore increase system reliability and uptime and reduce maintenanceoverhead.

Process 900 is shown to include comparing the amount of energy requiredto return the failsafe device to the failsafe position to the effectivecapacitance of the capacitor to determine a lifetime of the capacitor(step 910). In some embodiments, step 910 is performed as describedabove. Additionally or alternatively, step 910 may include performingany of steps 912-916. At step 912, a charge voltage required to achievethe amount of energy required to return the failsafe device to thefailsafe position is calculated given the effective capacitance of thecapacitor (e.g., capacitor 504). In some embodiments, charge voltagemodule 512 performs step 912 using Equation 6 above. At step 914, thecharge voltage is compared to a threshold voltage and/or a lifetimeparameter of the capacitor. For example, the charge voltage determinedin step 912 may be compared to a breakdown voltage of the capacitor. Atstep 916, based on the comparison, a lifetime of the capacitor isdetermined. In some embodiments, step 916 includes analyzing saveddevice data. For example, charge voltage module 512 may analyzepreviously determined charge voltages over time and determine from theslope of the relationship a predicted date that the charge voltagerequired for the capacitor exceeds operable levels (e.g., a breakdownvoltage, etc.).

Process 900 is shown to include sending, based on the determination ofthe lifetime of the capacitor, an indication of the lifetime of thecapacitor (step 920). In some embodiments, the indication is sent to BMScontroller 366. Additionally or alternatively, the indication may besent to a building operator. The indication may display remainingservice life of actuator 502. In some embodiments, the indication mayallow a user to change the operation of actuator 502. For example, auser may elect to slow down a drive speed of the failsafe device toprolong the life of the device. In some embodiments, the indicationincludes diagnostics associated with actuator 502. For example, theindication may include a plot of the effective capacitance of the deviceover time.

Referring now to FIG. 9B, process 902 is shown for determining a speedwith which to drive a failsafe device. Similar to process 900, process902 includes step 910. Step 910 may include steps 912-916, as describedin detail above with reference to FIG. 9A. Process 902 is shown toinclude determining, based on determining a lifetime of the capacitor, aspeed with which to drive the failsafe device (step 930). In someembodiments, step 930 includes prompting the user for input. Forexample, actuator 502 may allow a user to select a failsafe drivespeed/load tradeoff such as “if full stroke speed set to 120 secondsduring failsafe mode, actuator will drive ‘x’ N-m load for at least 5years; if full stroke speed set to 60 second during failsafe mode,actuator will drive ‘x’ N-m load for at least 3 years.” Additionally oralternatively, the drive speed may be determined automatically. Forexample, actuator 502 may reduce the speed of the actuator to half thenominal speed in response to determining that the failsafe device has10% of its lifetime remaining. Reducing the speed of the actuator mayextend the lifetime of the device.

Referring now to FIG. 10, a flowchart of a process 1000 for determininga time required to charge a capacitor (e.g., capacitor 504) is shown,according to some embodiments. Process 1000 may be configured to repeatfor each power cycle of power supply 506 to actuator 502. Additionallyor alternatively, process 1000 may repeat at scheduled intervals (e.g.,every day, etc.). In some embodiments, the results of process 1000 arestored in memory for later use. In various embodiments, process 1000uses the measured values from process 800. Process 1000 may be performedby various components within memory 532. In some embodiments, one ormore steps of process 1000 are performed by components outside of memory532.

Process 1000 is shown to include comparing the amount of energy to theeffective capacitance to determine a time required to charge thecapacitor (step 1010). In some embodiments, charge voltage module 512uses Equation 13 to calculate an amount of time required to charge thecapacitor (e.g., by multiplying the time constant by 5). In someembodiments, step 1010 includes steps 1012-1016. At step 1012, aneffective resistance associated with the amount of energy required toreturn the failsafe device to the failsafe position is determined. Insome embodiments, step 1012 is determined using the values from step810. At step 1014, a time constant associated with the capacitor isdetermined (e.g., using Equation 13, etc.). At step 1016, based on thetime constant, a time required to charge the capacitor is calculated(e.g., by multiplying the time constant τ by 5).

Process 1000 is shown to include sending, based on the determined timerequired to charge the capacitor, an indication of the time required tocharge the capacitor (step 1020). In some embodiments, the indication issent to BMS controller 366. Additionally or alternatively, theindication may be sent to a building operator. In some embodiments, theindication may indicate that capacitor 504 and/or the failsafe device(e.g., actuator 502) need to be replaced. In some embodiments, adifferent lifetime parameter may be sent. Lifetime parameters mayinclude an estimated lifetime of the capacitor (e.g., as discussed inreference to FIG. 9A), a time required to charge the capacitor, and/ordiagnostic results associated with the capacitor (e.g., testing thecapability of capacitor 504 to supply the power required to return thefailsafe device to the failsafe position as discussed above in referenceto FIG. 5). In some embodiments, lifetime parameters may include or bethe residual life (RL) ratio calculated via Equation 5. The residuallife ratio may provide an indication of the possible degradation of thecapacitor 504 and therefore be sent as a part of process 1000.

Referring now to FIG. 11, a diagram of boost-buck converter 515 forcharging capacitor 504 is shown, according to some embodiments.Specifically, FIG. 11 illustrates the a plurality of componentsincluding diodes, MOSFETs, resistors, capacitors, transistors, etc.,configured to step-up or step-down an input voltage (e.g., provided bypower supply 506 or an external source) within boost-buck converter 515.As described above, this boost-buck topology may be configurable toeither charge or deplete capacitor 504. In particular, a firstconfiguration may be established to step-down an input voltage to chargecapacitor 504, while a second configuration may be established tostep-up a voltage output of capacitor 504 for providing energy toprocessing circuit 536 and the other components of actuator 502.

As also described above, boost-buck converter 515 may be included involtage regulator 514 and/or power supply 506, or may be a separatecomponent located between capacitor 504 and one or more various othercomponents. In particular, all signals or energy flowing to or fromcapacitor 504 may pass through boost-buck converter 515 to either bestepped-up or down depending on the configuration. For example, whencharging capacitor 504 for failsafe, boost-buck converter 515 maystep-down the input voltage to capacitor 504 for slow and controlledcharging. When capacitor 504 is configured as a power source, boost-buckconverter 515 may step-up the voltage to power the various components ofactuator 502 (e.g., processing circuit 536, motor 516, etc.). In someembodiments, the various configurations are selected or controlled byprocessing circuit 536 or by another processing circuit or controller ofactuator 502 (not shown).

Configuration of Exemplary Embodiments

The construction and arrangement of the systems and methods as shown inthe various exemplary embodiments are illustrative only. Although only afew embodiments have been described in detail in this disclosure, manymodifications are possible (e.g., variations in sizes, dimensions,structures, shapes and proportions of the various elements, values ofparameters, mounting arrangements, use of materials, colors,orientations, etc.). For example, the position of elements may bereversed or otherwise varied and the nature or number of discreteelements or positions may be altered or varied. Accordingly, all suchmodifications are intended to be included within the scope of thepresent disclosure. The order or sequence of any process or method stepsmay be varied or re-sequenced according to alternative embodiments.Other substitutions, modifications, changes, and omissions may be madein the design, operating conditions and arrangement of the exemplaryembodiments without departing from the scope of the present disclosure.

The present disclosure contemplates methods, systems and programproducts on any machine-readable media for accomplishing variousoperations. The embodiments of the present disclosure may be implementedusing existing computer processors, or by a special purpose computerprocessor for an appropriate system, incorporated for this or anotherpurpose, or by a hardwired system. Embodiments within the scope of thepresent disclosure include program products comprising machine-readablemedia for carrying or having machine-executable instructions or datastructures stored thereon. Such machine-readable media may be anyavailable media that may be accessed by a general purpose or specialpurpose computer or other machine with a processor. By way of example,such machine-readable media may comprise RAM, ROM, EPROM, EEPROM, CD-ROMor other optical disk storage, magnetic disk storage or other magneticstorage devices, or any other medium which may be used to carry or storedesired program code in the form of machine-executable instructions ordata structures and which may be accessed by a general purpose orspecial purpose computer or other machine with a processor. Combinationsof the above are also included within the scope of machine-readablemedia. Machine-executable instructions include, for example,instructions and data which cause a general purpose computer, specialpurpose computer, or special purpose processing machines to perform acertain function or group of functions.

Although the figures show a specific order of method steps, the order ofthe steps may differ from what is depicted. Also two or more steps maybe performed concurrently or with partial concurrence. Such variationwill depend on the software and hardware systems chosen and on designerchoice. All such variations are within the scope of the disclosure.Likewise, software implementations could be accomplished with standardprogramming techniques with rule based logic and other logic toaccomplish the various connection steps, processing steps, comparisonsteps and decision steps.

What is claimed is:
 1. A method of determining a lifetime parameter of acapacitor in a failsafe device, the method comprising: measuring anamount of energy required to return the failsafe device to a failsafeposition; determining an effective capacitance of the capacitor; andcomparing the amount of energy to the effective capacitance to determinethe lifetime parameter of the capacitor.
 2. The method of claim 1,further comprising: determining, based on the effective capacitance, acharge voltage for the capacitor; and charging the capacitor using thecharge voltage with a boost buck circuit.
 3. The method of claim 1,wherein the lifetime parameter is a length of time associated with aremaining operational period of the capacitor and wherein the effectivecapacitance of the capacitor is determined using a measured valueassociated with energy used by a component of the fail safe device and afixed value representing energy.
 4. The method of claim 1, wherein thefailsafe device is an actuator.
 5. The method of claim 1, wherein thelifetime parameter is an amount of time required to charge the capacitorto a level associated with the amount of energy required to return thefailsafe device to the failsafe position.
 6. The method of claim 1,wherein the lifetime parameter is diagnostic information associated withphysically testing an ability of the capacitor to return the failsafedevice to the failsafe position.
 7. The method of claim 1, the methodfurther comprising sending the lifetime parameter to a buildingmanagement system (BMS), wherein the lifetime parameter indicates thatthe capacitor should be replaced.
 8. A method of charging a capacitor ina failsafe device, the method comprising: measuring an amount of energyrequired to return the failsafe device to a failsafe position; measuringan effective capacitance of the capacitor; determining, based on theeffective capacitance and the amount of energy, a charge voltage for thecapacitor; and charging the capacitor using the charge voltage.
 9. Themethod of claim 8, wherein the failsafe device is an actuator.
 10. Themethod of claim 8, further comprising: comparing the amount of energy tothe effective capacitance to determine a lifetime parameter of thecapacitor; and sending the lifetime parameter.
 11. The method of claim10, wherein the lifetime parameter indicates that the capacitor shouldbe replaced, wherein the effective capacitance of the capacitor isdetermined using a measured value associated with energy used by acomponent of the fail safe device and a fixed value representing energy.12. The method of claim 10, wherein the lifetime parameter is a lengthof time associated with a remaining operational period of the capacitorwherein cthe charging uses a boost buck circuit.
 13. The method of claim10, wherein the lifetime parameter is an amount of time required tocharge the capacitor to a level associated with the amount of energyrequired to return the failsafe device to the failsafe position.
 14. Themethod of claim 10, wherein the lifetime parameter is diagnosticinformation associated with physically testing an ability of thecapacitor to return the failsafe device to the failsafe position.
 15. Afailsafe device assembly, comprising: an actuator; a capacitor; and aprocessing circuit comprising a processor and memory, the memory havinginstructions stored thereon that, when executed by the processor, causethe processing circuit to: compare an amount of energy required toreturn the actuator to a failsafe position to an effective capacitanceof the capacitor to determine an operational parameter of the actuator;and operate the actuator according to the operational parameter.
 16. Thefailsafe device assembly of claim 15, wherein the memory has furtherinstructions stored thereon that, when executed by the processor, causethe processing circuit to: determine, based on the effectivecapacitance, a charge voltage for the capacitor; and charge thecapacitor using the charge voltage.
 17. The failsafe device assembly ofclaim 15, wherein the operational parameter describes a speed with whichthe actuator returns to the failsafe position.
 18. The failsafe deviceassembly of claim 17, wherein determining the operational parameter ofthe actuator further includes receiving a selection of the speed from auser.
 19. The failsafe device assembly of claim 15, wherein the memoryhas further instructions stored thereon that, when executed by theprocessor, cause the processing circuit to: compare the amount of energyto the effective capacitance to determine a lifetime parameter of thecapacitor; and send the lifetime parameter.
 20. The failsafe deviceassembly of claim 19 further comprising an artificial intelligencemodule.